910 search results for "how to import image file to R"

Visually Comparing Return Distributions

January 18, 2013
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Visually Comparing Return Distributions

Here is a spot of code to create a series of small multiples for comparing return distributions. You may have spotted this in a presentation I posted about earlier, but I’ve been using it here and there and am finally satisfied that it is a generally useful view, so I functionalized it. When visually comparing

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Power Calculations – relationship between test power, effect size and sample size

January 17, 2013
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Power Calculations – relationship between test power, effect size and sample size

I was interested in modeling the relationship between the power and sample size, while holding the significance level constant (p = 0.05) , for the common two-sample t-Test. Luckily R has great support for power analysis and I found the function I was looking for in the package pwr. To calculate the power for the two-sample T-test

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If SPSS can factor analyze MaxDiff scores, why can’t R?

January 17, 2013
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If SPSS can factor analyze MaxDiff scores, why can’t R?

Answer:  The variance-covariance matrix containing all the MaxDiff scores is not invertible.  R tells you that, either with an error message or a warning.  SPSS, at least earlier versions still in use, runs the factor analysis witho...

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Creating a random calendar with R

January 14, 2013
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Creating a random calendar with R

Sometimes this is my life. But it’s so satisfying when you write a program that saves you time! Here is an example. The Problem:  For several years at Hopkins I have been involved in teaching a large (500+ person) introductory Biostatistics class. This … Continue reading →

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Using TeXmacs as an interface for R

January 14, 2013
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Using TeXmacs as an interface for R

Using TeXmacs as an interface for R (part 1)(This post was copied from my post at wordpress. Because I didn't manage to switch r-bloggers.com to use that blog, I'm reposting it here....) A nice, but not very well known, interface to R isTeXmacs. (I...

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Decluttering ordination plots in vegan part 2: orditorp()

January 13, 2013
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Decluttering ordination plots in vegan part 2: orditorp()

In the earlier post in this series I looked at the ordilabel() function to help tidy up ordination biplots in vegan. An alternative function vegan provides is orditorp(), the last four letters abbreviating the words text or points. That is … Continue reading →

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Decluttering ordination plots in vegan part 1: ordilabel()

January 12, 2013
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Decluttering ordination plots in vegan part 1: ordilabel()

In an earlier post I showed how to customise ordination diagrams produced by our vegan package for R through use of colours and plotting symbols. In a series of short posts I want to cover some of the options available … Continue reading →

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DC R Meetup: “Analyze US Government Survey Data with R”

January 10, 2013
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DC R Meetup: “Analyze US Government Survey Data with R”

I really enjoyed tonight’s DC R Meetup, presented by the prolific Anthony Damico. I’ve met Anthony before to discuss whether the Census Bureau could either… publish R-readable … Continue reading →

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R for actuarial science

January 10, 2013
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R for actuarial science

As mentioned in the Appendix of Modern Actuarial Risk Theory, “R (and S) is the ‘lingua franca’ of data analysis and statistical computing, used in academia, climate research, computer science, bioinformatics, pharmaceutical industry, customer analytics, data mining, finance and by some insurers. Apart from being stable, fast, always up-to-date and very versatile, the chief advantage of R is that...

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Monotonic deshrinking in weighted averaging models

January 5, 2013
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Monotonic deshrinking in weighted averaging models

Weighted averaging regression and calibration is the most widely used method for developing a palaeolimnological transfer function. Such models are used to reconstruct properties of the past lake environment such as pH, total phosphorus, and water temperature with, it has … Continue reading →

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